Utilization of the nutrients in the soluble and insoluble fractions of fungal mycelium by larvae of the stag beetle, Dorcus rectus (Coleoptera: Lucanidae)
Larvae of the stag beetle, Dorcus rectus, feed on decaying wood, which they digest with the aid of symbiotic yeasts; however, they can be successfully reared on artificial diets containing only fungal tissue. In this study we tested whether D. rectus larvae can utilize fungal cell walls, which are a...
| Main Authors: | , |
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| Format: | Article |
| Language: | English |
| Published: |
Institute of Entomology, Biology Centre, Czech Academy of Science
2013-12-01
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| Series: | European Journal of Entomology |
| Subjects: | |
| Online Access: | https://www.eje.cz/artkey/eje-201304-0009_Utilization_of_the_nutrients_in_the_soluble_and_insoluble_fractions_of_fungal_mycelium_by_larvae_of_the_stag_be.php |
| Summary: | Larvae of the stag beetle, Dorcus rectus, feed on decaying wood, which they digest with the aid of symbiotic yeasts; however, they can be successfully reared on artificial diets containing only fungal tissue. In this study we tested whether D. rectus larvae can utilize fungal cell walls, which are an insoluble component of mycelium. Lyophilized Bjerkandera adusta mycelium cultured in potato-dextrose liquid medium consisted of a 47.6% hot-water insoluble fraction by mass, which contains 53.7% of the total nitrogen in the mycelium. D. rectus larvae that hatched from surface-sterilized eggs were reared for 14 days on agar-based diets containing either the soluble fraction, insoluble fraction or both, extracted from 100 mg of mycelium. The larvae increased in mass most on the mixed diet, and there was no difference in their growth on the mixed and positive control diets. Both the soluble and insoluble fractions improved larval growth compared to the negative control diet; however, the growth rates were much lower than those expected from the nitrogen dose-growth response curve obtained in a previous study. Addition of b-chitin to the soluble fraction did not positively affect larval growth. Therefore, we conclude that (1) D. rectus larvae need both the soluble and insoluble fractions of mycelium and (2) the larvae digest the insoluble fraction using their own enzymes. |
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| ISSN: | 1210-5759 1802-8829 |